This invention relates to a solar heat collector of the type in which a panel is attached, for example, to the roof of a building in spaced relation from the roof so that a flow space for air or other fluid is defined between the panel and the roof. When solar rays strike the panel, a certain amount of the solar energy is absorbed as heat and the remainder of the energy is reflected from the panel. The heat which is absorbed raises the temperature of the air in the flow space and such air may be used to heat the building.
The invention has more particular reference to a solar panel whose upper side is defined by a series of substantially V-shaped channels. Radiation at certain incident angles reflects back and forth between the two opposing side walls of each channel before being reflected from the channel. As a result, more energy is absorbed and less is reflected so as to increase the effectiveness of the panel.